Ritlecitinib

Generic Name: Ritlecitinib

Brand Names: Litfulo

Drug Type: Small Molecule

Chemical Formula: C_₁₅H_₁₉N_₅O

CAS Number: 1792180-81-4

Unique Ingredient Identifier: 2OYE00PC25

Background: Ritlecitinib (PF-06651600) is a highly selective inhibitor of Janus kinase 3 (JAK3) and the tyrosine kinase expressed in hepatocellular carcinoma (TEC) kinase family. In June 2023, it was approved by the FDA for the treatment of severe alopecia areata in adults and adolescents 12 years and older. It was further approved by the EMA in September 2023. Ritlecitinib is administered orally and is the first member of its class.

Ritlecitinib binds covalently to Cys-909 of JAK3, a site where other JAK isoforms have a serine residue. This makes ritlecitinib a highly selective and irreversible JAK3 inhibitor. Other kinases have a cysteine at a position equivalent to Cys-909 in JAK3, and several of them belong to the TEC kinase family. It has been suggested that the dual activity of ritlecitinib toward JAK3 and the TEC kinase family block cytokine signaling as well as the cytolytic activity of T cells, both implicated in the pathogenesis of alopecia areata.

Indication: Ritlecitinib is indicated for the treatment of severe alopecia areata in adults and adolescents 12 years and older. It is not recommended for use in combination with other JAK inhibitors, biologic immunomodulators, cyclosporine or other potent immunosuppressants.

Associated Conditions: Severe Alopecia Areata (AA)

Clinical Trials

Long-Term PF-06651600 for the Treatment of Alopecia Areata

Phase 3

Active, not recruiting

Conditions: Alopecia Areata

Interventions: Drug: PF-06651600
Biological: Tetanus and diphtheria toxoids and acellular pertussis (Tdap) vaccine
Biological: Meningococcal (groups A, C, W-135 and Y [ACWY]) oligosaccharide diphtheria CRM197 conjugate vaccine

First Posted Date: 2019-07-05

Last Posted Date: 2025-04-23

Lead Sponsor: Pfizer

Target Recruit Count: 1052

Registration Number: NCT04006457

Locations: 🇵🇱
EMC Instytut Medyczny S.A. Przychodnia przy ul. Lowieckiej we Wroclawiu, Wroclaw, Poland
🇵🇱
Cityclinic Przychodnia Lekarsko Psychologiczna Matusiak Spółka Partnerska, Wroclaw, Poland
🇵🇱
Centrum Medyczne OPOROW, Wroclaw, Poland

and more 140 locations

Bioavailability Study of PF-06651600 Formulations in Healthy Participants

Phase 1

Completed

Conditions: Healthy Volunteers

Interventions: Drug: PF-06651600

First Posted Date: 2019-07-02

Last Posted Date: 2019-11-01

Lead Sponsor: Pfizer

Target Recruit Count: 12

Registration Number: NCT04004663

Locations: 🇧🇪
Brussels Clinical Research Unit, Brussels, Be-bru, Belgium

Study to Characterize Absorption, Distribution, Metabolism and Excretion of 14C PF-06651600 and to Evaluate the Absolute Oral Bioavailability and Fraction Absorbed of PF-06651600.

Phase 1

Completed

Conditions: Healthy Volunteers

Interventions: Drug: 14C-PF-06651600
Drug: 14C-PF-06651600 IV
Drug: PF-06651600

First Posted Date: 2019-04-29

Last Posted Date: 2019-07-24

Lead Sponsor: Pfizer

Target Recruit Count: 6

Registration Number: NCT03929510

Locations: 🇳🇱
PRA Health Sciences Utrecht, Utrecht, Netherlands
🇳🇱
PRA Health Sciences, Groningen, Netherlands

ESTIMATION OF THE EFFECT OF MULTIPLE DOSE PF-06651600 ON THE PHARMACOKINETICS OF SINGLE DOSE MIDAZOLAM AND EFAVIRENZ

Phase 1

Completed

Conditions: Healthy Subjects

Interventions: Drug: midazolam
Drug: PF-06651600
Drug: efavirenz

First Posted Date: 2018-12-04

Last Posted Date: 2019-03-26

Lead Sponsor: Pfizer

Target Recruit Count: 12

Registration Number: NCT03762928

Locations: 🇺🇸
Pfizer New Haven Clinical Research Unit, New Haven, Connecticut, United States

A Phase 2b Study To Evaluate The Efficacy And Safety Profile Of PF-06651600 And PF-06700841 In Active Non-segmental Vitiligo Subjects

Phase 2

Completed

Conditions: Active Non-segmental Vitiligo

Interventions: Drug: PF-06651600
Drug: placebo
Drug: PF06700841
Device: narrow-band UVB phototherapy

First Posted Date: 2018-10-23

Last Posted Date: 2022-03-25

Lead Sponsor: Pfizer

Target Recruit Count: 366

Registration Number: NCT03715829

Locations: 🇺🇸
Advanced Skin and MOHS Surgery Center, c/o TrialSpark, Inc., Chicago, Illinois, United States
🇦🇺
Veracity Clinical Research Pty Ltd, Woolloongabba, Queensland, Australia
🇦🇺
The Royal Melbourne Hospital, Parkville, Victoria, Australia

and more 87 locations

A STUDY TO ESTIMATE THE EFFECT OF PF-06651600 ON THE PHARMACOKINETICS (PK) OF ORAL CONTRACEPTIVE (OC)

Phase 1

Completed

Conditions: Healthy Females

Interventions: Drug: PF-06651600
Drug: Ethinyl estradiol (EE) and levonogestrel (LN)

First Posted Date: 2018-07-31

Last Posted Date: 2019-04-09

Lead Sponsor: Pfizer

Target Recruit Count: 12

Registration Number: NCT03608241

Locations: 🇺🇸
Quotient Sciences-Miami, Inc., Miami, Florida, United States
🇺🇸
Quotient Sciences, Coral Gables, Florida, United States

Study To Evaluate The Efficacy And Safety Of Oral PF-06651600 And PF-06700841 In Subjects With Moderate To Severe Crohn's Disease

Phase 2

Completed

Conditions: Crohn's Disease

Interventions: Drug: Placebo PF-06700841
Drug: PF-06651600 Placebo
Drug: PF-06700841
Drug: PF-06651600

First Posted Date: 2018-01-10

Last Posted Date: 2024-10-30

Lead Sponsor: Pfizer

Target Recruit Count: 244

Registration Number: NCT03395184

Locations: 🇺🇦
Regional Municipal Non-profit Enterprise "Chernivtsi Regional Clinical Hospital", Surgery Department, Chernivtsi, Ukraine
🇺🇸
Dothan Surgery Center, Dothan, Alabama, United States
🇺🇸
Gut P.C., dba Digestive Health Specialists of the Southeast, Dothan, Alabama, United States

and more 183 locations

Safety and Pharmacokinetic Study of PF-06651600 in Japanese Healthy Volunteers

Phase 1

Completed

Conditions: Healthy

Interventions: Drug: PF-06651600
Drug: Placebo

First Posted Date: 2017-07-28

Last Posted Date: 2017-12-06

Lead Sponsor: Pfizer

Target Recruit Count: 6

Registration Number: NCT03232905

Locations: 🇧🇪
Pfizer Clinical Research Unit, Brussels, Belgium

Study To Evaluate The Efficacy And Safety Profile Of PF-06651600 And PF-06700841 In Subjects With Alopecia Areata

Phase 2

Completed

Conditions: Alopecia Areata

Interventions: Drug: PF-06651600
Drug: Placebo
Drug: PF-06700841

First Posted Date: 2016-11-29

Last Posted Date: 2020-05-26

Lead Sponsor: Pfizer

Target Recruit Count: 142

Registration Number: NCT02974868

Locations: 🇺🇸
Yale Hearing and Balance Center, New Haven, Connecticut, United States
🇺🇸
Yale School of Medicine, New Haven, Connecticut, United States
🇺🇸
Yale New Haven Hospital, New Haven, Connecticut, United States

and more 52 locations

Study To Assess The Efficacy And Safety Of Pf-06651600 In Subjects With Rheumatoid Arthritis With An Inadequate Response To Methotrexate

Phase 2

Completed

Conditions: Rheumatoid Arthritis

Interventions: Drug: PF-06651600
Drug: Placebo

First Posted Date: 2016-11-21

Last Posted Date: 2018-12-04

Lead Sponsor: Pfizer

Target Recruit Count: 70

Registration Number: NCT02969044

Locations: 🇺🇸
Clayton Medical Associates, PC, Saint Louis, Missouri, United States
🇺🇸
California Medical Research Associates Inc., Northridge, California, United States
🇺🇸
Altoona Center For Clinical Research, Duncansville, Pennsylvania, United States

and more 27 locations

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